Electronic equipments involving numbers of semiconductor devices are indispensable from our daily life. With the advancement of electronic technology, the electronic equipment has becomes smaller in size and has to execute and perform more and more complicated and multiple functions. Thus, the electronic equipment becomes more compact involving more numbers of electronic components, and becomes more complex in structure involving high density of input/output (I/O) terminals within such a small area.
A wafer level packaging (WLP) technology has been gaining in popularity. This technology provides a wafer level manufacturing of the semiconductor device with high functions and performances while small size of the semiconductor device. During manufacturing of the semiconductor device, a surface mounting technology (SMT) is employed for miniaturizing the semiconductor device. The semiconductor device includes a substrate mounting on another substrate, so that a pad of the substrate is bonded and electrically connected with a pad of another substrate through a solder ball.
The pads of the substrate are formed on a top surface of the substrate by various methods. However, the pads formed by different methods would provide different reliability with respect to drop test, thermal cycling, bending or etc. For example, some pads would be able to withstand a high stress level and thus cracks would not be developed easily, while some pads would be able to withstand a high temperature and thus delamination from the substrate is minimized.
As such, there is a continuous demand on improving the configuration of the pads on the substrate and manufacturing operations of the pads to optimize reliability of the pads and solve the above deficiencies.